to be honest, I think that this effect is based more on hype/marketing than actually making a perfect overclocking motherboard
BlackOps - I had an ES board (from the QF programme). Works well only with a QX9650 when raw CPU freq is needed. Overclocking with other CPU models / efficency / FSB+memory clocking was rather poor, definitely not a multi-purpose board like *COUGH* ASUS X38/X48-series.
Classified - I had a few (owned one myself + tested a couple of others' boards at events), just couldn't see why everyone was bragging so much about it .. may be because I'm from Europe and eVGA service/availability is far from the best over here.
R3E Black - didn't have one. But from the feedback I heard, it's a poinless product since it couldn't do anything a cheaper R3F wasn't capable of .. except, may be, 4-way SLI which not that much people care about.